Nonzero orbital momenta in triangle graphs and the picture of moving singularities

It is shown that nonzero orbital momenta in the nuclear vertex and the vertex of the secondary interaction in the triangle graph lead to a more clear picture corresponding to the moving complex singularity compared with the case of zero orbital momenta and constant vertices. The peak in the distribution of the invariant mass of the final particles becomes narrower and its shift with momentum transfer becomes more distinct. It opens the possibility to observe this picture experimentally. A formula is obtained for the triangle graph for nuclear reactions including the effect of nontrivial nuclear and secondary interaction vertices. It has the form of one-fold integral in coordinate space including a new function corresponding to the rescattering vertex. The properties of this function are described for various kinds of the vertex